The present invention relates to automatic door assemblies. In particular, the present invention relates to a sliding door assembly having a damping device that provides controlled resistance to swinging movement of a panel during breakout.
Sliding door assemblies known heretofore conventionally have a frame assembly with a pair of non-sliding panels mounted thereto and one or two sliding door panels that move in a generally rectilinear manner between opened and closed positions. The non-sliding panels are positioned such that they are on opposing lateral sides of the sliding panels when the sliding door panels are closed. During normal operation, a power-operated overhead door operator moves the sliding panel(s) between the opened and closed positions thereof.
Oftentimes, either the sliding panels, the non-sliding door panels, or both are provided with the capability to open outwardly in a swinging manner under an application of manual force to allow persons to pass through the door assembly during emergency conditions wherein the door operator is unable to open the sliding panel(s). This capability, referred to in the art as xe2x80x9cbreakout,xe2x80x9d is usually required by state or local building codes as a safety measure for allowing exit from buildings during fires, power outages, and other such emergency situations wherein the door operator may be unable to function properly.
It has been known in the field of automatic door assemblies to provide the panels with breakout capability with a yieldable detent device for maintaining a breakout panel in its normal, non-breakout condition until a predetermined amount of force is applied to the panel. The amount of force required to move the panel in a breakout manner usually has a maximum set by local codes. However, once the panel has been moved out of its normal, non-breakout condition, these yieldable devices do not function to control the manner in which the panel continues to open.
To control the manner in which the breakout panel swings once breakout has begun and the panel is released from the above-described yieldable detent device, damping devices have been connected at one end to the top rail of the breakout panel and at the other end to the header that houses the door controlling unit. These devices are designed to provide controlled resistance to the swinging breakout movement of the panel. Specifically, these devices prevent the panel from being thrown open in an uncontrolled manner by persons seeking exit through the door assembly and also prevent high winds from acting on the panel and also throwing it open in a uncontrolled manner.
One example of a known damping device comprises a U-shaped track structure that defines a U-shaped channel and a rod with a plastic block on one end thereof. The track structure fixedly connects to the top rail of the door panel in the longitudinal direction thereof, the rod pivotally connects to the header of the door frame, and the rod and track structure are assembled together with the plastic block fit tightly in the U-shaped channel. As the panel is swung open during breakout, the plastic block slides within the U-shaped channel so that the friction between the block and the channel walls provides a controlled resistance to the panel""s movement.
One problem with the use of these extendible and retractable devices can be appreciated from viewing FIG. 1. FIG. 1 is a schematic overhead view of a conventional door assembly 100 with a header 102, a breakout panel 104 opened 90xc2x0 from normal, and a damping device 106 for controlling the swinging movement of the panel 104, such as the U-shaped channel and block arrangement mentioned above. The device 106 has a metal track 103 with interior surfaces and a plastic friction block 105 tightly received in the track 103. The block 105 is mounted on a metal rod 107 and a spring 109 is disposed between the block 105 and the end of the track to resist the door panel""s opening movements. The panel 104 is pivotally connected to the header 102 by pivot pin 108. When a load is applied to the panel 104, as indicated at FL, the pivotal connection between the rod 107 and the block 105 of the damping device 106 acts as fulcrum point. Also, the pivot pin 108 provides a fulcrum point. Accordingly, the application of load FL creates reaction forces at the pivotal connection between the rod 107 and the block 105 and on the pin 108. These reaction forces are illustrated by the arrows shown in FIG. 1.
It is to be understood that the reaction forces on the pivot pin may be created by structures other than an extendible door swing controlling device. For example, a shopping cart may become wedged between the breakout panel and the building exterior as the panel is being opened. Also, the breakout panel may contact a portion of the frame assembly as it approaches opening 180 degrees, thereby providing the panel with a leverage point. Thus, it could be broadly stated that these reaction forces are created as a result of a load that is applied to the breakout panel at a point distal the pivot pin which tends to pivot the breakout panel about a second point located intermediate the first point and the pivot pin.
Of particular concern in this arrangement are the reaction forces applied to the pivot pin 108. In conventional panels, the bracket that carries the pivot pin 108 is only attached to the interior of the vertical side rail or stile. Thus, the forces applied to the pivot pin 108 will be transferred to and be borne by the stile. The problem with this is that most side stiles are thin-walled metal extrusions and may become deformed under the forces applied to the pivot pin 108. Specifically, brackets that have been previously mounted inside side stiles are mounted by fasteners to only one side wall thereof with spacing provided between the bracket and the other side walls. As a result, when a force is applied to the bracket, this force is localized on the fasteners that mount the bracket. In addition, the spacing provided between the other side walls of the stile and the bracket allows the bracket to move under this force, thereby inwardly deforming the side wall to which it is mounted, particularly at the points where the fasteners are located. Permanent deformation of the side stile may result if the loads and reaction forces involved are high enough. One possible solution would be to use a stile with thicker walls. However, the costs of metal extrusions increase significantly as the wall thickness increases and likewise the overall weight of the panel increases.
In the above-described arrangement with the bracket mounted to one wall of the stile, the pin is normally extendible and retractable and a spring is mounted inside the bracket to bias the pin to its extended position. The advantage of this arrangement is that it makes the door panel relatively easy to install. Specifically, the installer retracts the pin, positions the door panel in place with the pin in alignment with its corresponding aperture on the door carrier or header, and then releases the pin for its spring-biased movement into the corresponding aperture.
Another prior art construction alleviates the stile deformation problem mentioned above with respect to the arrangement with the bracket mounted to a side wall of the stile. This second prior art construction is shown in FIG. 2. This construction, generally indicated at 200, comprises an upper bracket 202 that mounts to the sliding door panel carrier and a lower bracket 204 that mounts to the top rail of the door panel. The pivot pin 206 is fixed to the lower bracket 204 and pivotally mounted to the upper bracket by a ball bearing assembly 207 so that the upper and lower brackets 202, 204 pivot relative to one another. When the door panel is assembled, the reaction forces discussed above are distributed to the top rail of the door panel in the longitudinal direction thereof. As a result, the problems associated with the deformation of the stile wall are obviated because all the reaction forces are transmitted to the top rail. Because these reaction forces are being transmitted to the top rail in its longitudinal direction, the top rail is capable of withstanding relatively high reaction forces without deformation.
The problem with this arrangement is that it is relatively difficult to install in comparison with the previously described arrangement with the bracket mounted to the stile interior. To install the construction shown in FIG. 2, the upper bracket 202 must first be mounted to the door panel carrier while the lower bracket 204 is disconnected from the door panel. Then, the lower bracket 204 must be pivoted out to about ninety degrees relative to the upper bracket 202 and then connected to the door panel""s top rail by a plurality of fasteners. This installation procedure is relatively difficult and inefficient compared to the retractable pivot pin arrangement described above.
Thus, it can be appreciated from the foregoing that each of the above-described described prior art constructions has certain advantages and disadvantages concerning load distribution and installation. It would be desirable to provide a device that provides the advantages of both of the above-discussed prior art constructions while eliminating their disadvantages. To date, it is believed that no such device has been provided and thus, there exists a need in the art for such a device.
It is therefore an objective of the present invention to meet the above-described need. To meet this objective, the present invention provides a sliding door assembly that comprises a frame assembly, a sliding panel carrier, and a sliding panel mounted to the sliding panel carrier. The sliding panel carrier is mounted to the frame assembly for generally rectilinear movement to enable movement of the sliding panel between a closed position and an open position. The sliding panel carrier provides a pivot pin receiving opening. A power-operated door controlling unit is operatively connected to the sliding panel carrier and moves the same in a generally rectilinear manner between the open and closed positions.
The sliding panel has a mounting bracket mounted to the top rail thereof. The bracket provides a pivot pin that moves between an extended and retracted positions. The sliding panel is mounted to the sliding panel carrier by inserting the pivot pin into the pivot pin receiving opening. As a result, the sliding panel can swing relative to the frame assembly though a breakout movement under an application of manual force from (1) a normal, non-breakout position to (2) a breakout position. The term xe2x80x9cbracketxe2x80x9d is intended to generically encompass any structure suitable for mounting the pivot pin to the top rail of the panel. The bracket, the pivot pin, and the pivot pin receiving opening are constructed and arranged such that, when the door assembly is installed and the sliding panel is moved in a swinging manner to the breakout position thereof, a load applied to the sliding panel that tends to pivot the sliding panel about a point spaced radially the pivot pin creates a reaction force that is applied to the pivot pin which reaction force is transmitted to the top rail of the sliding panel as a result of the mounting bracket being mounted thereon and the pivot pin being received in the pivot pin receiving opening.
As a result of this construction, the problems associated with reaction forces causing side stile deformation are obviated because such forces are transferred to and absorbed by the top rail. Specifically, the top rail is better suited to handle these reaction forces because it is oriented in the same general plane in which the reaction forces are normally created, whereas the side stile is oriented generally perpendicular to such a plane and, as a result, transferal of reaction forces causes inward deformation of the stile walls. Further, the installation of the sliding panel can be easily and effectively performed using the extendible and retractable pivot pin arrangement. Thus, the door assembly of the present invention achieves the advantages of the prior art arrangements without the associated disadvantages.
The bracket arrangement of the present invention may also be applied to non-sliding panels. In fact, the present invention contemplates applying the principles of the present invention to any type of panel in any type of sliding door assembly that is capable of breakout movement.
Other objects, features, and advantages of the present invention will become apparent from the following detailed description, the accompanying drawings, and the appended claims.